1. Field of the Invention
The present invention relates to a bulb socket which is less liable to come off a housing while maintaining waterproofness.
2. Description of the Related Art
Waterproofness is demanded of lamps installed around car bodies of automobiles or on two-wheeled vehicles (motorcycles), and thus bulbs are often mounted in rubber sockets which are then mounted in housings (casings in which the rubber sockets are mounted). Such a bulb socket is described in Japanese Patent Laid-Open No. 2000-48922 (FIG. 1). Also, a bulb socket mounted in a housing using a bayonet structure is described in Japanese Utility Model Laid-Open No. 5-72076 (FIG. 1).
With the bulb socket described in Japanese Patent Laid-Open No. 2000-48922 (FIG. 1), a rubber socket cylindrical in shape is mounted by simply being inserted in a circular opening (socket mounting slot) of the housing, and thus the socket is liable to come off (fall off) the housing. In contrast, the bulb socket described in Japanese Utility Model Laid-Open No. 5-72076 (FIG. 1) is mounted in a housing using a bayonet structure (a structure in which the bulb socket is inserted, rotated, and held firmly in the housing) which can prevent the bulb socket from coming off.
However, the bayonet structure is generally suited for high-rigidity parts made of resin, metal, or the like, but is not suitable for low-rigidity parts such as rubber sockets. Specifically, if the bayonet structure is used with a low-rigidity part, when the part is inserted into another part (such as a housing) and rotated, the part deforms easily (twists due to the rotation) and the bayonet structure does not follow the rotation, making it difficult to assemble the part to the other part in an intended state. Even if the part is assembled, since the bayonet structure deforms easily due to external force, the part tends to come off the other part easily.